Bis(benzimidazole) derivatives serving as potassium blocking agents

ABSTRACT

This invention relates to novel potassium channel blocking agents, and their use in the preparation of pharmaceutical compositions. 
     Moreover the invention is directed to pharmaceutical compositions useful for the treatment or alleviation of diseases or disorders associated with the activity of potassium channels, in particular asthma, cystic fibrosis, chronic obstructive pulmonary disease and rhinorrhea, convulsions, vascular spasms, coronary artery spasms, renal disorders, polycystic kidney disease, bladder spasms, urinary incontinence, bladder outflow obstruction, irritable bowel syndrome, gastrointestinal dysfunction, secretory diarrhoea, ischaemia, cerebral ischaemia, ischaemic hearth disease, angina pectoris, coronary hearth disease, traumatic brain injury, psychosis, anxiety, depression, dementia, memory and attention deficits, Alzheimer&#39;s disease, dysmenorrhea, narcolepsy, Reynaud&#39;s disease, intermittent claudication, Sjorgren&#39;s syndrome, migraine, arrhythmia, hypertension, absence seizures, myotonic muscle dystrophia, xerostomi, diabetes type II, hyperinsulinemia, premature labor, baldness, cancer, and immune suppression.

This application is a divisional of application Ser. No. 09/750,345filed on Dec. 29, 2000 now U.S. Pat. No. 6,380,180, which is adivisional of application Ser. No. 09/347,514 filed on Jul. 2, 1999, nowU.S. Pat. No. 6,194,447, which is a conversion of ProvisionalApplication No.: 60/092,218 filed Jul. 8, 1998, the entire contents ofwhich are hereby incorporated by reference and for which priority isclaimed under 35 U.S.C. §120; and this application claims priority ofApplication No. PA 1998 00865 filed in Denmark on Jul. 2, 1998 under 35U.S.C. §119.

TECHNICAL FIELD

This invention relates to novel potassium channel blocking agents, andtheir use in the preparation of pharmaceutical compositions.

Moreover the invention is directed to pharmaceutical compositions usefulfor the treatment or alleviation of diseases or disorders associatedwith the activity of potassium channels, in particular asthma, cysticfibrosis, chronic obstructive pulmonary disease and rhinorrhea,convulsions, vascular spasms, coronary artery spasms, renal disorders,polycystic kidney disease, bladder spasms, urinary incontinence, bladderoutflow obstruction, irritable bowel syndrome, gastrointestinaldysfunction, secretory diarrhoea, ischaemia, cerebral ischaemia,ischaemic hearth disease, angina pectoris, coronary hearth disease,traumatic brain injury, psychosis, anxiety, depression, dementia, memoryand attention deficits, Alzheimer's disease, dysmenorrhea, narcolepsy,Reynaud's disease, intermittent claudication, Sjorgren's syndrome,migraine, arrhythmia, hypertension, absence seizures, myotonic muscledystrophia, xerostomi, diabetes type II, hyperinsulinemia, prematurelabor, baldness, cancer, and immune suppression.

BACKGROUND ART

Ion channels are transmembrane proteins, which catalyze the transport ofinorganic ions across cell membranes. The ion channels participate inprocesses as diverse as the generation and timing of action potentials,synaptic transmissions, secretion of hormones, contraction of muscles,etc.

All mammalian cells express potassium (K⁺) channels in their cellmembranes, and the channels play a dominant role in the regulation ofthe membrane potential. In nerve and muscle cells they regulate thefrequency and form of the action potential, the release ofneurotransmitters, and the degree of broncho- and vasodilation.

From a molecular point of view, the K⁺ channels represent the largestand most diverse group of ion channels. For an overview they can bedivided into five large subfamilies: Voltage-activated K⁺ channels(K_(v)), long QT related K⁺ channels (KvLQT), inward rectifiers(K_(IR)), two-pore K⁺ channels (K_(TP)), and calcium-activated K⁺channels (K_(ca)).

The latter group, the Ca²⁺-activated K⁺ channels, consists of threewell-defined subtypes: SK channels, IK channels and BK channels. SK, IKand BK refer to the single-channel conductance (Small, Intermediate andBig conductance K channel). The SK, IK, and BK channels exhibitdifferences in e.g. voltage- and calcium-sensitivity, pharmacology,distribution and function.

SK channels are present in many central neurons and ganglia, where theirprimary function is to hyperpolarize nerve cells following one orseveral action potentials, in order to prevent long trains ofepileptogenic activity to occur. The SK channels are also present inseveral peripheral cells including skeletal muscle, gland cells, livercells, and T-lymphocytes. The significance of SK channels in normalskeletal muscle is not clear, but their number is significantlyincreased in denervated muscle, and the large number of SK channels inthe muscle of patients with myotonic muscle dystrophia, suggest a rolein the pathogenesis of the disease.

Studies indicate that K⁺ channels may be a therapeutic target in thetreatment of a number of diseases including asthma, cystic fibrosis,chronic obstructive pulmonary disease and rhinorrhea, convulsions,vascular spasms, coronary artery spasms, renal disorders, polycystickidney disease, bladder spasms, urinary incontinence, bladder outflowobstruction, irritable bowel syndrome, gastrointestinal dysfunction,secretory diarrhoea, ischaemia, cerebral ischaemia, ischaemic hearthdisease, angina pectoris, coronary hearth disease, traumatic braininjury, psychosis, anxiety, depression, dementia, memory and attentiondeficits, Alzheimer's disease, dysmenorrhea, narcolepsy, Reynaud'sdisease, intermittent claudication, Sjorgren's syndrome, migraine,arrhythmia, hypertension, absence seizures, myotonic muscle dystrophia,xerostomi, diabetes type II, hyperinsulinemia, premature labor,baldness, cancer, and immune suppression.

A number of neuromuscular blocking agents with effect on SK channelsexist, e.g. apamin, atracurium, pancuronium and tubocurarine.

WO 97/48705 discloses a particular group of chemical compounds useful ascalcium activated potassium channel blocking agents. However, theirselectivity in respect of the SK channel is not disclosed.

U.S. Pat. Nos. 5,739,127 and 5,760,230 disclose other groups of chemicalcompounds acting on potassium channels.

SUMMARY OF THE INVENTION

The present invention resides in the provision of novel chemicalcompounds capable of selectively blocking SK channels, or subtypes of SKchannels.

Moreover the invention is directed to pharmaceutical compositions usefulor the treatment or alleviation of diseases or disorders associated withthe activity of potassium channels, including diseases or conditionslike respiratory diseases such as asthma, cystic fibrosis, chronicobstructive pulmonary disease and rhinorrhea, convulsions, vascularspasms, coronary artery spasms, renal disorders, polycystic kidneydisease, bladder spasms, urinary incontinence, bladder outflowobstruction, irritable bowel syndrome, gastrointestinal dysfunction,secretory diarrhoea, ischaemia, cerebral ischaemia, ischaemic hearthdisease, angina pectoris, coronary hearth disease, traumatic braininjury, psychosis, anxiety, depression, dementia, memory and attentiondeficits, Alzheimer's disease, dysmenorrhea, narcolepsy, Reynaud'sdisease, intermittent claudication, Sjorgren's syndrome, migraine,arrhythmia, hypertension, absence seizures, myotonic muscle dystrophia,xerostomi, diabetes type II, hyperinsulinemia, premature labor,baldness, cancer, and immune suppression.

Accordingly, in its first aspect, the invention provides novel chemicalcompound of the invention is one selected from the group represented bythe general formulas I to VIII, below.

In another aspect, the invention provides pharmaceutical compositionscomprising an effective amount of a chemical compound of the invention.

In further aspects the invention relates to the use of a chemicalcompound of the invention for the manufacture of a medicament for thetreatment or alleviation of diseases or disorders associated with theactivity of potassium channels, and to method of treatment oralleviation of disorders or conditions responsive to blockade ofpotassium channels.

DETAILED DISCLOSURE OF THE INVENTION

Potassium Channel Blocking Agents

In its first aspect, the invention provides novel chemical compounds.The chemical compounds of the invention is particularly useful aspotassium channel blocking agents.

Thus, the invention provides a potassium channel blocking agent, inparticular a SK channel blocking agent, selected from the grouprepresented by the general formulas I to VIII, below.

a bis(aminobenzimidazole) derivative, wherein

A represents a spacing group containing of from 1 to 20 atoms, a spacinggroup having a chain length of from 1 to 20 atoms, or a spacing grouphaving a chain length comprising of from 1 to 20 separate bonds.

The spacing group, A, may in particular be

a linear or branched alkylene chain having of from 1 to 15 carbon atoms,which alkylene group may be interrupted by one or more oxygen or sulphuratoms, or by one or more groups of the formula —NR′—, or ═NR′, whereinR′ represents hydrogen or alkyl;

a radical of the formula —(CH₂)_(a)-D-(CH₂)_(b)—, wherein a and b, whichmay be identical or different, represent the number 0, 1, 2, 3, 4 or 5,and D represents a cycloalkyl group; or

an aryl group of from 6 to 12 carbon atoms, which aryl group may inparticular be a phenyl group or a biphenyl group.

In a most preferred embodiment, A is a spacing group selected from thoseA-groups described in the working examples and in Tables 1, 7 and 8,below, and those B-groups described in the working examples and in Table8, below.

In a most preferred embodiment, the compound of Formula I is

1,3-Bis[(2-aminobenzimidazol-1-yl)methyl]cyclohexane;

1,6-Bis(2-aminobenzimidazol-1-yl)hexane;

1,4-Bis(2-aminobenzimidazol-1-yl)butane;

1,3-Bis(2-aminobenzimidazol-1-yl)propane;

1,2-Bis(2-aminobenzimidazol-1-yl)ethane;

α,α′-Bis(2-aminobenzimidazol-1-yl)-para-xylene;

α,α′-Bis(2-aminobenzimidazol-1-yl)-meta-xylene;

1,3-Bis(2-aminobenzimidazol-1-yl)benzene;

3,3′-Bis(2-aminobenzimidazol-1-yl)biphenyl; or

cis-1,5-bis(2-amino-1-benzimidazolyl)cyclooctane.

an aminobenzimidazole derivative, wherein

R¹ represents

a mono- or polycyclic aryl group, an aralkyl group, or a mono- orpoly-heterocyclic group, which aryl, aralkyl and heterocyclic groups mayoptionally be substituted one or more times with substituents selectedamong halogen; alkyl; alkoxy; cyano; trifluoromethyl; phenyl; guanidino,which guanidino may optionally be substituted with alkyl, phenyl orbenzyl; primary, secondary or tertiary amino groups, i.e. an amino groupsubstituted once or twice with an alkyl group (—NH₂; —NH-alkyl; and—N(alkyl)₂); or

a mono- or polycyclic aryl group as described above, attached to a mono-or poly-heterocyclic group described above; and

R² represents hydrogen, an alkyl group, or CF₃.

An example of a preferred aryl group is phenyl.

An example of a preferred aralkyl group is benzyl.

Examples of preferred heterocyclic groups are pyrazolyl, imidazolyl,thiazolyl, and isothiazolyl.

In a more preferred embodiment R¹ is a mono- or polycyclic aryl group ora mono- or poly-heterocyclic group selected from those R¹-groupsdescribed in the working examples and in Table 2, below. In a morepreferred embodiment R¹ is phenyl, benzyl, pyrazolyl, imidazolyl,thiazolyl, or isothiazolyl.

In a most preferred embodiment R² represents a substituent selected fromthose R²-groups described in the working examples and in Table 2, below.

In a most preferred embodiment, the compound of Formula II is

2-Amino-1-[4-(4-chlorophenyl)-2-thiazolyl]benzimidazole;

2-Amino-1-(4-dimethylaminobenzyl)-5-trifluoromethylbenzimidazole;

2-Amino-1-(4-phenyl-2-thiazolyl)benzimidazole;

2-Amino-1-[3-(1,3,5-trimethylpyrazol-4-yl)phenyl]benzimidazole;

2-Amino-1-(4-(N-(2-thiazolyl)amino)phenyl)benzimidazole;

1-(4-(2-Aminobenzimidazol-1-yl)phenyl)-3-phenylguanidine;

2-Amino-1-(4-acetamidophenyl)benzimidazole; or

2-Amino-1-(4-aminophenyl)-benzimidazole.

a guanidine derivative, wherein

R¹ and R², which may be identical or different, represent hydrogen,alkyl, a mono- or poly-heterocyclic group, a mono- or polycyclic arylgroup, or an aralkyl group, which heterocyclic, aryl or aralkyl groupsmay optionally be substituted one or more times with substituentsselected among halogen; alkyl; alkoxy; cyano; trifluoromethyl; phenyl;guanidino, which guanidino may optionally be substituted with alkyl,phenyl or benzyl; or primary, secondary or tertiary amino groups, i.e.an amino group substituted once or twice with an alkyl group (—NH₂;—NH-alkyl; and —N(alkyl)₂).

Examples of preferred heterocyclic monocyclic groups of the inventionare furanyl, imidazolyl, isothiazolyl, isoxazolyl, 1,2,3-oxadiazolyl,1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolyl,pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl,thiadiazolyl, thiazolyl, and thienyl.

Examples of preferred heterocyclic polycyclic groups of the inventionare benzimidazolyl, indolyl, isoquinolyl, quinolyl, acridinyl,phenazinyl, and phenthiazinyl.

Examples of preferred aryl groups of the invention are phenyl, naphthyland anthracenyl.

A preferred aralkyl group of the invention is benzyl.

In a most preferred embodiment, R¹ represents substituent selected fromthose R¹-groups described in the working examples and in Table 3, below.

In a most preferred embodiment, R² represents a substituent selectedfrom those R²-groups described in the working examples and in Table 3,below.

In a most preferred embodiment the compound of Formula III is

1-(2-Methoxy-5-(trifluoromethyl)phenyl)-3-(3-(trifluoromethyl)phenyl)guanidine;

1-(4-Chlorobenzyl)-3-(3-triflouromethylphenyl)guanidine;

1-(5-Chloro-2-methoxyphenyl)-3-(3-(trifluoromethyl)phenyl)guanidine;

1,3-Bis(3-(trifluoromethyl)phenyl)guanidine;

1-(2-Bromo-5-(trifluoromethyl)phenyl)-3-(5-(trifluoromethyl)phenyl)guanidine;

1-(4-aminophenyl)guanidine;

α,α′-Bis(3-phenylguanidine-1-yl)-para-xylene; or

6-Amino-3-guanidinoacridine.

a guanidine derivative, wherein

R¹ and R², which may be identical or different, represents hydrogen, amono- or polycyclic aryl group, or an aralkyl group, which aryl oraralkyl groups may optionally be substituted one or more times withsubstituents selected among halogen, alkyl, alkoxy, cyano,trifluoromethyl, primary, secondary or tertiary amino groups, i.e. anamino group substituted once or twice with an alkyl group (—NH₂;—NH-alkyl; and —N(alkyl)₂); and

R³ represents

a divalent mono- or poly-heterocyclic group, a divalent mono- orpolycyclic aryl group, or a divalent aralkyl group, which heterocyclic,aryl, aralkyl may optionally be substituted one or more times withsubstituents selected among halogen, alkyl, alkoxy, cyano,trifluoromethyl, primary, secondary or tertiary amino groups, whichsecondary and tertiary amino groups may substituted (once or twice) withan alkyl group or a phenyl group, said phenyl group optionally beingsubstituted one or more times with substituents selected among halogen,trifluoromethyl, and/or cyano;

a divalent radical of the formula —(CH₂)_(c)—, wherein c is a number 1,2, 3, 4 or 5; or

a mono- or polycyclic aryl group as described above, attached to anothermono- or polycyclic aryl group as described above, optionally attachedvia an oxygen, sulphur, or nitrogen atom to form a divalent bridginggroup, in which bridging group the nitrogen atom may additionally besubstituted with a mono- or polycyclic aryl group as described above toform a tertiary amino group.

Examples of preferred R¹ and R² groups are phenyl and benzyl, optionallysubstituted one or more times with halogen and/or a primary amino group.The substitutions may preferably be in the ortho- and/or para-positions.

Examples of preferred R³ groups are divalent phenyl groups, or divalentphenyl groups bridged by a nitrogen atom to form a secondary or tertiaryamino group, which tertiary amino group may preferably be substitutedwith an additional phenyl group, which phenyl group may optionally besubstituted with halogen, trifluoromethyl or cyano.

In a most preferred embodiment R¹ represents a substituent selected fromthose R¹-groups described in the working examples and in Table 4, below.

In a most preferred embodiment R² represents a substituent selected fromthose R²-groups described in the working examples and in Table 4, below.

In a most preferred embodiment R³ represents a substituent selected fromthose R³-groups described in the working examples and in Table 4, below.

In a most preferred embodiment the compound of Formula IV is

5-Chloro-1,3-bis-(4-chlorobenzyl)-2-iminobenzimidazoline;

12-(3-Chloro-4-cyanophenyl)-6-imino-5,7,12-triaza-di-benzo[a,f]cyclooctane;

1-(2-Aminophenyl)-2-imino-3-phenyl-imidazolidine; or

6-Imino-5,7,12-triaza-di-benzo[a,f]cyclooctane.

Formula V

R—L—R  (V)

representing symmetric compounds wherein

L represents a spacing group containing of from 1 to 20 atoms, a spacinggroup having of from 2 to 20 atoms, or a spacing group comprising offrom 2 to 20 separate bonds; and

R represents

a mono- or polycyclic aryl group, an aralkyl group, or one or more mono-or poly-heterocyclic group(s), which heterocyclic group preferablycomprises one or more nitrogen atoms as the heteroatom(s),

or a mono- or polycyclic aryl group or an aryl group attached to aheterocyclic group as described above.

The R-group holding a tertiary nitrogen atom may in particular be madequaternary using an alkylation agent, preferably an alkyl halide, suchas the chloride, bromide or iodide of methyl or ethyl.

The spacing group, L, may in particular be

a linear or a branched alkylene chain having of from 2 to 5 carbonatoms;

a radical of the formula —(CH₂)_(a)-D-(CH₂)_(b)—, wherein a and b, whichmay be identical or different, represent the number 0, 1, 2, 3, 4 or 5,and D represents a cycloalkyl group;

an aryl group of from 6 to 12 carbon atoms, which aryl group may inparticular be a biphenyl group; or

a mono- or poly-heterocyclic group, which heterocyclic group preferablycomprise one or more nitrogen atoms as the heteroatom(s).

An example of a preferred aryl group is phenyl.

Examples of preferred heterocyclic groups are pyrolidinyl, pyrrolyl,pyrazolyl, imidazolyl, pyridinyl, piperidinyl, pyridazinyl, pyrimidinyl,pyrazinyl, and piperazinyl.

The R group may preferably be

a nitrogen containing heterocyclic ring attached to a nitrogencontaining hetero-aromatic ring (heteroaryl), wherein the nitrogencontaining heterocyclic ring preferably is piperazinyl, and the nitrogencontaining heteroaryl preferably is pyrimidinyl; or

a nitrogen containing hetero-aromatic ring (heteroaryl), wherein thenitrogen containing heterocyclic ring preferably is benzimidazolyl,attached to an aralkyl group, wherein the aralkyl group preferably isbenzyl.

In a most preferred embodiment L represents a spacing group selectedfrom those L-groups described in the working examples and in Table 5,below.

In a most preferred embodiment R represents a substituent selected fromthose R-groups described in the working examples and in Table 5, below.

In a most preferred embodiment the compound of Formula V is

α, α′-Bis(1-(2-pyrimidyl)piperazin-4-yl)-para-xylene;

α, α′-Bis(1-(2-pyrimidyl)-4-methylpiperazinium-4-yl)-para-xylene; or

1,4-Bis(1-benzylbenzimidazol-2-yl)piperazine.

wherein

R¹, R², and R⁴, which may be identical or different, represent hydrogen,alkyl, phenyl or benzyl, which phenyl or benzyl may optionally besubstituted one or more times with substituents selected among halogen,trifluoromethyl, and cyano; and

R³ represents hydrogen, halogen, trifluoromethyl, cyano, alkyl, phenylor benzyl.

In a most preferred embodiment R¹ represents a substituent selected fromthose R¹-groups described in the working examples and in Table 6, below.

In a most preferred embodiment R² represents a substituent selected fromthose R²-groups described in the working examples and in Table 6, below.

In a most preferred embodiment R³ represents a substituent selected fromthose R³-groups described in the working examples and in Table 6, below.

In a most preferred embodiment R⁴ represents a substituent selected fromthose R⁴-groups described in the working examples and in Table 6, below.

In a most preferred embodiment the compound of Formula VI is

1-(4′-Chlorobenzyl)-2-dimethylamino)-5-trifluoromethylbenzimidazoline.

a bis(benzimidazole) derivative, wherein

A is a spacing group with the meanings described for group A underFormula I, above, and

X represents

hydrogen, halogen, trifluoromethyl, cyano, alkoxy, alkyl, phenyl orbenzyl, which phenyl or benzyl may optionally be substituted one or moretimes with substituents selected among halogen, trifluoromethyl, andalkyl; or

a mono- or poly-heterocyclic group, preferably comprising one or morenitrogen, oxygen or sulphur atoms as heteroatom(s), which heterocyclicgroup may optionally be substituted one or more times with substituentsselected among halogen, trifluoromethyl, alkoxy or alkyl.

In a most preferred embodiment A represents a spacing group selectedfrom those A-groups described in the working examples and in Table 7,below.

In a most preferred embodiment X represents a substituent selected fromthose X-groups described in the working examples and in Table 7, below.

In a most preferred embodiment the compound of Formula VII is

cis,trans-1,4-Bis[(2-chlorobenzimidazol-1-yl)methyl]cyclohexane;

cis,trans-1,4-Bis[2-(1-pyrrolidinyl)benzimidazol-1-yl)methyl]cyclohexane;

cis,trans-1,4-Bis[(2-(4-morfolinyl)benzimidazol-1-yl)methyl]cyclohexane;

cis,trans-1,4-Bis[(2-(1-methylpiperazine-4-yl)benzimidazol-1-yl)methyl]cyclohexane;or

α,α′-Bis(1-benzimidazolyl)-meta-xylene.

a bis(benzimidazolium) derivative, wherein

A and B, which may be identical or different, represent spacing groupsas described for group A under Formula I, above;

X is as described under Formula VII, above; and

Y represents a halide, and is preferably chlorine, bromine or iodine.

In a most preferred embodiment A and B represents a spacing groupselected from those A-groups described in the working examples and inTables 1, 7 and 8, below.

In a most preferred embodiment the compound of Formula VIII is1,1′-(α,α′-para-xylylene)-3,3′-(α,α′-meta-xylylene)-bis(benzimidazolium).

Definition of Substituents

In the context of this invention a spacing group designates asubstituent that links the two parts of the molecule and bring theseparts into a relatively determined spatial inter-relationship. Thespacing group may also be termed a linking group or a bridging group.The spacing group of the invention should link the two parts of themolecule in a not too close and not too far distance from each another.It is currently believed that spacing groups comprising of from 2 to 20atoms fulfill this requirement. Examples of such spacing groups aredescribed herein, and summarized below.

Spacing Group Name —(CH₂)₁₀— decamethylene; —(CH₂)₈— octamethylene;—(CH₂)₆— hexamethylene; —(CH₂)₅— pentamethylene; —(CH₂)₄—tetramethylene; —(CH₂)₃— trimethylene; —(CH₂)₂— dimethylene;—N(CH₃)—CH₂—N(CH₃)— N,N′-dimethyl-diamino-methylene;—N(CH₃)—CH₂—CH₂—N(CH₃)— N,N′-dimethyl-diamino-dimethylene;—N(CH₃)—CH₂—CH₂—CH₂—N(CH₃)— N,N′-dimethyl-diamino-trimethylene;

(cis and/or trans)-1,5-cyclooctylene;

(cis and/or trans)-1,3-dimethyl- cyclohexane-α,α′-diyl;

para-xylene-α,α′-diyl;

meta-xylene-α,α′-diyl;

1,3-phenylene;

biphenyl-3,3′-diyl;

4,4′-dimethyl-bibenzyl-α,α′-diyl;

4,4′-dimethyl-diphenylmethane-α,α′-diyl;

4,4′-dimethyl-cis/trans-stilbene-α,α′-diyl;

2,6-bis(4′-methyl-phenyl)pyridine-α,α′-diyl;

3,3′-dimethyl-biphenyl-α,α′-diyl;

2,7-dimethyl-9H-fluorene-α,α′-diyl;

In the context of this invention halogen represents a fluorine, achlorine, a bromine or a iodine atom.

In the context of this invention an alkyl group designates a univalentsaturated, straight or branched hydrocarbon chain. The hydrocarbon chainpreferably contain of from one to eighteen carbon atoms (C₁₋₁₈-alkyl),more preferred of from one to six carbon atoms (C₁₋₆-alkyl; loweralkyl), including pentyl, isopentyl, neopentyl, tertiary pentyl, hexyland isohexyl. In a preferred embodiment alkyl represents a C₁₋₄-alkylgroup, including butyl, isobutyl, secondary butyl, and tertiary butyl.In a preferred embodiment of this invention alkyl represents aC₁₋₃-alkyl group, which may in particular be methyl, ethyl, propyl orisopropyl.

In the context of this invention a cycloalkyl group designates a cyclicalkyl group, preferably containing of from three to seven carbon atoms(C₃₋₇-cycloalkyl), including cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl and cycloheptyl.

In the context of this invention an alkoxy group designates an“alkyl-O-” group, wherein alkyl is as defined above.

In the context of this invention an amino group may be a primary (—NH₂),secondary (—NH-alkyl), or tertiary (—N(alkyl)₂) amino group, i.e. it maybe substituted once or twice with an alkyl group as defined above.

In the context of this invention a mono- or polycyclic aryl groupdesignates a monocyclic or polycyclic aromatic hydrocarbon group.Examples of preferred aryl groups of the invention are phenyl, naphthyland anthracenyl.

In the context of this invention an aralkyl group designates a mono- orpolycyclic aryl group as defined above, which aryl group is attached toan alkyl group as also defined above. An example of a preferred aralkylgroup of the invention benzyl.

In the context of this invention a mono- or poly-heterocyclic group is amono- or polycyclic compound, which holds one or more heteroatoms in itsring structure. One or more of the ring structures may in particular bearomatic (i.e. a heteroaryl). Preferred heterocyclic monocyclic groupsof the invention are 5- or 6 membered heterocyclic monocyclic groups.Examples of preferred heterocyclic monocyclic groups of the inventionare furanyl, imidazolyl, isothiazolyl, isoxazolyl, 1,2,3-oxadiazolyl,1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolyl,pyrazinyl, pyrazolyl, pyridazinyl, pyridyl, pyrimidinyl, pyrrolyl,thiadiazolyl, thiazolyl, and thienyl. Examples of preferred heterocyclicpolycyclic groups of the invention are benzimidazolyl, indolyl,isoquinolyl and quinolyl.

Also, in the context of this invention, a chemical compound comprising atertiary amino group may also be made quaternary (quaternized) using analkylation agent, in particular an alkyl halide, preferably thechloride, bromide or iodide of methyl or ethyl.

Specific Examples

In its most preferred embodiment, the chemical compound of the inventionis one selected from those described in the working examples or inTables 1-8, below.

TABLE 1 Chemical Compounds of Formula I

Compound A Example 1a*

2 1b —(CH₂)₆— 1 1c —(CH₂)₄— 1 1d —(CH₂)₃— 1 1e —(CH₂)₂— 2 1f

2 1g

2 1h

2 1i

2 1j

18 *cis/trans mixture

TABLE 2 Chemical Compounds of Formula II

Compound R₁ R₂ Example 2a

H 17/A 2b

CF₃ 17/A 2c

H 17/A 2d

H 17 2e

H 17/A 2f

H 17/A

TABLE 3 Chemical Compounds of Formula III

Compound R₁ R₂ Example 3a

17/E 3b

17/F 3c

17/E 3d

17/E 3e

17/F 3f

H 6 3g

7 3h

H 8

TABLE 4 Chemical Compounds of Formula IV

Compound R₁ R₂ R₃ Example 4a

17/F 4b H H

17/G 4c

—CH₂CH₂— 17/G 4d H H

17/G

TABLE 5 Chemical Compounds of Formula V

Compound L R Example 5a

13 5b

14 5c

15

TABLE 6 Chemical Compounds of Formula VI

Compound R₁ R₂ R₃ R₄ Example 6d CH₃ CH₃ CF₃

16

TABLE 7 Chemical Compounds of Formula VII

Compound X A Example 7a Cl

11 7b

12 7c

13 7d

14 7e H

 9

TABLE 8 Chemical Compounds of Formula VIII (VIII)

Com- pound X A B Example 7f H

10

Steric Isomers

The chemical compounds of the present invention may exist in (+) and (−)forms as well as in racemic forms. The racemates of these isomers andthe individual isomers themselves are within the scope of the presentinvention.

Racemic forms can be resolved into the optical antipodes by known ismethods and techniques. One way of separating the diastereomeric saltsis by use of an optically active acid, and liberating the opticallyactive amine compound by treatment with a base. Another method forresolving racemates into the optical antipodes is based uponchromatography on an optical active matrix. Racemic compounds of thepresent invention can thus be resolved into their optical antipodes,e.g., by fractional crystallization, of d- or I- (tartrates, mandelates,or camphorsulphonate) salts for example.

The chemical compounds of the present invention may also be resolved bythe formation of diastereomeric amides by reaction of the chemicalcompounds of the present invention with an optically active activatedcarboxylic acid such as that derived from (+) or (−) phenylalanine, (+)or (−) phenylglycine, (+) or (−) camphanic acid or by the formation ofdiastereomeric carbamates by reaction of the chemical compound of thepresent invention with an optically active chloroformate or the like.

Additional methods for the resolving the optical isomers are known inthe art. Such methods include those described by Jaques J, Collet A, &Wilen S in “Enantiomers, Racemates, and Resolutions”, John Wiley andSons, New York (1981).

Moreover, some of the chemical compounds of the invention being oximes,may thus exist in two forms, syn- and anti-form (Z- and E-form),depending on the arrangement of the substituents around the —C═N— doublebond. A chemical compound of the present invention may thus be the syn-or the anti-form (Z- and E-form), or it may be a mixture hereof.

Pharmaceutically Acceptable Salts

The chemical compound of the invention may be provided in any formsuitable for the intended administration. Suitable forms includepharmaceutically (i.e. physiologically) acceptable salts, and pre- orprodrug forms of the chemical compound of the invention.

Examples of pharmaceutically acceptable addition salts include, withoutlimitation, the non-toxic inorganic and organic acid addition salts suchas the hydrochloride derived from hydrochloric acid, the hydrobromidederived from hydrobromic acid, the nitrate derived from nitric acid, theperchlorate derived from perchloric acid, the phosphate derived fromphosphoric acid, the sulphate derived from sulphuric acid, the formatederived from formic acid, the acetate derived from acetic acid, theaconate derived from aconitic acid, the ascorbate derived from ascorbicacid, the benzenesulfonate derived from benzensulfonic acid, thebenzoate derived from benzoic acid, the cinnamate derived from cinnamicacid, the citrate derived from citric acid, the embonate derived fromembonic acid, the enantate derived from enanthic acid, the fumaratederived from fumaric acid, the glutamate derived from glutamic acid, theglycolate derived from glycolic acid, the lactate derived from lacticacid, the maleate derived from maleic acid, the malonate derived frommalonic acid, the mandelate derived from mandelic acid, themethanesulfonate derived from methane sulphonic acid, thenaphthalene-2-sulphonate derived from naphtalene-2-sulphonic acid, thephthalate derived from phthalic acid, the salicylate derived fromsalicylic acid, the sorbate derived from sorbic acid, the stearatederived from stearic acid, the succinate derived from succinic acid, thetartrate derived from tartaric acid, the toluene-p-sulphonate derivedfrom p-toluene sulphonic acid, and the like. Such salts may be formed byprocedures well known and described in the art.

Other acids such as oxalic acid, which may not be consideredpharmaceutically acceptable, may be useful in the preparation of saltsuseful as intermediates in obtaining a chemical compound of theinvention and its pharmaceutically acceptable acid addition salt.

Metal salts of a chemical compound of the invention includes alkalimetal salts, such as the sodium salt of a chemical compound of theinvention containing a carboxy group.

The chemical compound of the invention may be provided in dissoluble orindissoluble forms together with a pharmaceutically acceptable solventssuch as water, ethanol, and the like. Dissoluble forms may also includehydrated forms such as the monohydrate, the dihydrate, the hemihydrate,the trihydrate, the tetrahydrate, and the like. In general, thedissoluble forms are considered equivalent to indissoluble forms for thepurposes of this invention.

Methods of Preparation

The chemical compounds of the invention may be prepared by conventionalmethods of chemical synthesis, e.g. those described in the workingexamples. The starting materials for the processes described in thepresent application are known or may readily be prepared by conventionalmethods from commercially available chemicals.

The end products of the reactions described herein may be isolated byconventional techniques, e.g. by extraction, crystallization,distillation, chromatography, etc.

Biological Activity

The chemical compounds of the invention have been subjected to in vitroexperiments and found particularly useful as potassium channel blockingagents. More particularly the compound of the invention are capable ofselectively blockade of SK channels, e.g. SK1, SK2 and/or SK3 channels.

As described in the working examples, the compounds tested all showed abiological activity determined as IC₅₀ in the sub-micromolar and lowmicromolar range, i.e. of from below 1 to above 10 μM. Preferredcompounds of the invention show a biological activity determined asdescribed herein in the in the sub-micromolar and micromolar range, i.e.of from below 1 to about 100 μM.

Therefore, in another aspect, the invention relates to the use of achemical compound of the invention for the manufacture of medicaments,which medicament may be useful for the treatment or alleviation of adisease or a disorder associated with the activity of potassiumchannels, in particular SK channels.

In a more preferred embodiment, the chemical compound of the inventionmay be use for the manufacture of medicaments for the treatment oralleviation of diseases or conditions like respiratory diseases such asasthma, cystic fibrosis, chronic obstructive pulmonary disease andrhinorrhea, convulsions, vascular spasms, coronary artery spasms, renaldisorders, polycystic kidney disease, bladder spasms, urinaryincontinence, bladder outflow obstruction, irritable bowel syndrome,gastrointestinal dysfunction, secretory diarrhoea, ischaemia, cerebralischaemia, ischaemic hearth disease, angina pectoris, coronary hearthdisease, traumatic brain injury, psychosis, anxiety, depression,dementia, memory and attention deficits, Alzheimer's disease,dysmenorrhea, narcolepsy, Reynaud's disease, intermittent claudication,Sjorgren's syndrome, migraine, arrhythmia, hypertension, absenceseizures, myotonic muscle dystrophia, xerostomi, diabetes type II,hyperinsulinemia, premature labor, baldness, cancer, and immunesuppression.

Pharmaceutical Compositions

In yet another aspect the invention provides novel pharmaceuticalcompositions comprising a therapeutically effective amount of thechemical compound of the invention.

While a chemical compound of the invention for use in therapy may beadministered in the form of the raw chemical compound, it is preferredto introduce the active ingredient, optionally in the form of aphysiologically acceptable salt, in a pharmaceutical compositiontogether with one or more adjuvants, excipients, carriers and/ordiluents.

In a preferred embodiment, the invention provides pharmaceuticalcompositions comprising the chemical compound of the invention, or apharmaceutically acceptable salt or derivative thereof, together withone or more pharmaceutically acceptable carriers therefor and,optionally, other therapeutic and/or prophylactic ingredients. Thecarrier(s) must be “acceptable” in the sense of being compatible withthe other ingredients of the formulation and not deleterious to therecipient thereof.

Pharmaceutical compositions of the invention may be those suitable fororal, rectal, nasal, topical (including buccal and sub-lingual),transdermal, vaginal or parenteral (including intramuscular,sub-cutaneous and intravenous) administration, or those in a formsuitable for administration by inhalation or insufflation.

The chemical compound of the invention, together with a conventionaladjuvant, carrier, or diluent, may thus be placed into the form ofpharmaceutical compositions and unit dosages thereof, and in such formmay be employed as solids, such as tablets or filled capsules, orliquids such as solutions, suspensions, emulsions, elixirs, or capsulesfilled with the same, all for oral use, in the form of suppositories forrectal administration; or in the form of sterile injectable solutionsfor parenteral (including subcutaneous) use. Such pharmaceuticalcompositions and unit dosage forms thereof may comprise conventionalingredients in conventional proportions, with or without additionalactive compounds or principles, and such unit dosage forms may containany suitable effective amount of the active ingredient commensurate withthe intended daily dosage range to be employed.

The chemical compound of the present invention can be administered in awide variety of oral and parenteral dosage forms. It will be obvious tothose skilled in the art that the following dosage forms may comprise,as the active component, either a chemical compound of the invention ora pharmaceutically acceptable salt of a chemical compound of theinvention.

For preparing pharmaceutical compositions from a chemical compound ofthe present invention, pharmaceutically acceptable carriers can beeither solid or liquid. Solid form preparations include powders,tablets, pills, capsules, cachets, suppositories, and dispersiblegranules. A solid carrier can be one or more substances which may alsoact as diluents, flavoring agents, solubilizers, lubricants, suspendingagents, binders, preservatives, tablet disintegrating agents, or anencapsulating material.

In powders, the carrier is a finely divided solid which is in a mixturewith the finely divided active component.

In tablets, the active component is mixed with the carrier having thenecessary binding capacity in suitable proportions and compacted in theshape and size desired.

The powders and tablets preferably contain from five or ten to aboutseventy percent of the active compound. Suitable carriers are magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,starch, gelatin, tragacanth, methylcellulose, sodiumcarboxymethylcellulose, a low melting wax, cocoa butter, and the like.The term “preparation” is intended to include the formulation of theactive compound with encapsulating material as carrier providing acapsule in which the active component, with or without carriers, issurrounded by a carrier, which is thus in association with it.Similarly, cachets and lozenges are included. Tablets, powders,capsules, pills, cachets, and lozenges can be used as solid formssuitable for oral administration.

For preparing suppositories, a low melting wax, such as a mixture offatty acid glyceride or cocoa butter, is first melted and the activecomponent is dispersed homogeneously therein, as by stirring. The moltenhomogenous mixture is then poured into convenient sized moulds, allowedto cool, and thereby to solidify.

Compositions suitable for vaginal administration may be presented aspessaries, tampons, creams, gels, pastes, foams or sprays containing inaddition to the active ingredient such carriers as are known in the artto be appropriate.

Liquid preparations include solutions, suspensions, and emulsions, forexample, water or water-propylene glycol solutions. For example,parenteral injection liquid preparations can be formulated as solutionsin aqueous polyethylene glycol solution.

The chemical compound according to the present invention may thus beformulated for parenteral administration (e.g. by injection, for examplebolus injection or continuous infusion) and may be presented in unitdose form in ampoules, pre-filled syringes, small volume infusion or inmulti-dose containers with an added preservative. The compositions maytake such forms as suspensions, solutions, or emulsions in oily oraqueous vehicles, and may contain formulation agents such as suspending,stabilizing and/or dispersing agents. Alternatively, the activeingredient may be in powder form, obtained by aseptic isolation ofsterile solid or by lyophilization from solution, for constitution witha suitable vehicle, e.g. sterile, pyrogen-free water, before use.

Aqueous solutions suitable for oral use can be prepared by dissolvingthe active component in water and adding suitable colorants, flavors,stabilizing and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing thefinely divided active component in water with viscous material, such asnatural or synthetic gums, resins, methylcellulose, sodiumcarboxymethylcellulose, or other well known suspending agents.

Also included are solid form preparations which are intended to beconverted, shortly before use, to liquid form preparations for oraladministration. Such liquid forms include solutions, suspensions, andemulsions. These preparations may contain, in addition to the activecomponent, colorants, flavors, stabilizers, buffers, artificial andnatural sweeteners, dispersants, thickeners, solubilizing agents, andthe like

For topical administration to the epidermis the chemical compoundaccording to the invention may be formulated as ointments, creams orlotions, or as a transdermal patch. Ointments and creams may, forexample, be formulated with an aqueous or oily base with the addition ofsuitable thickening and/or gelling agents. Lotions may be formulatedwith an aqueous or oily base and will in general also contain one ormore emulsifying agents, stabilizing agents, dispersing agents,suspending agents, thickening agents, or coloring agents.

Compositions suitable for topical administration in the mouth includelozenges comprising the active agent in a flavored base, usually sucroseand acacia or tragacanth; pastilles comprising the active ingredient inan inert base such as gelatin and glycerine or sucrose and acacia; andmouthwashes comprising the active ingredient in a suitable liquidcarrier.

Solutions or suspensions are applied directly to the nasal cavity byconventional means, for example with a dropper, pipette or spray. Thecompositions may be provided in single or multi-dose form. In the lattercase of a dropper or pipette, this may be achieved by the patientadministering an appropriate, predetermined volume of the solution orsuspension. In the case of a spray, this may be achieved for example bymeans of a metering atomizing spray pump.

Administration to the respiratory tract may also be achieved by means ofan aerosol formulation in which the active ingredient is provided in apressurized pack with a suitable propellant such as a chlorofluorocarbon(CFC) for example dichlorodifluoromethane, trichlorofluoromethane, ordichlorotetrafluoroethane, carbon dioxide, or other suitable gas. Theaerosol may conveniently also contain a surfactant such as lecithin. Thedose of drug may be controlled by provision of a metered valve.

Alternatively the active ingredients may be provided in the form of adry powder, for example a powder mix of the compound in a suitablepowder base such as lactose, starch, starch derivatives such ashydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP).Conveniently the powder carrier will form a gel in the nasal cavity. Thepowder composition may be presented in unit dose form for example incapsules or cartridges of, e.g., gelatin, or blister packs from whichthe powder may be administered by means of an inhaler.

In compositions intended for administration to the respiratory tract,including intranasal compositions, the compound will generally have asmall particle size for example of the order of 5 microns or less. Sucha particle size may be obtained by means known in the art, for exampleby micronization.

When desired, compositions adapted to give sustained release of theactive ingredient may be employed.

The pharmaceutical preparations are preferably in unit dosage forms. Insuch form, the preparation is subdivided into unit doses containingappropriate quantities of the active component. The unit dosage form canbe a packaged preparation, the package containing discrete quantities ofpreparation, such as packaged tablets, capsules, and powders in vials orampoules. Also, the unit dosage form can be a capsule, tablet, cachet,or lozenge itself, or it can be the appropriate number of any of thesein packaged form.

Tablets or capsules for oral administration and liquids for intravenousadministration and continuous infusion are preferred compositions.

Further details on techniques for formulation and administration may befound in the latest edition of Remington's Pharmaceutical Sciences(Maack Publishing Co., Easton, Pa.).

A therapeutically effective dose refers to that amount of activeingredient which ameliorates the symptoms or condition. Therapeuticefficacy and toxicity, e.g. ED₅₀ and LD₅₀, may be determined by standardpharmacological procedures in cell cultures or experimental animals. Thedose ratio between therapeutic and toxic effects is the therapeuticindex and may be expressed by the ratio LD₅₀/ED₅₀. Pharmaceuticalcompositions which exhibit large therapeutic indexes are preferred.

The dose administered must of course be carefully adjusted to the age,weight and condition of the individual being treated, as well as theroute of administration, dosage form and regimen, and the resultdesired, and the exact dosage should of course be determined by thepractitioner.

The active ingredient may be administered in one or several doses perday. It is presently contemplated that compositions containing of fromabout 0.1 to about 500 mg of active ingredient per unit dosage,preferably of from about 1 to about 100 mg, most preferred of from about1 to about 10 mg, are suitable for therapeutic treatments.

Methods of Treatment

In another aspect the invention relates to a method of treating oralleviating a disorder or disease of a living animal body, including ahuman, which disorder or disease is responsive to blockade of thepotassium channel, in particular the SK channel, which method comprisescomprising administering to such a living animal body, including ahuman, in need thereof a therapeutically-effective amount of a compoundof the invention.

The in a preferred embodiment of the method of the invention, thedisease or disorder is asthma, cystic fibrosis, chronic obstructivepulmonary disease and rhinorrhea, convulsions, vascular spasms, coronaryartery spasms, renal disorders, polycystic kidney disease, bladderspasms, urinary incontinence, bladder outflow obstruction, irritablebowel syndrome, gastrointestinal dysfunction, secretory diarrhoea,ischaemia, cerebral ischaemia, ischaemic hearth disease, anginapectoris, coronary hearth disease, traumatic brain injury, psychosis,anxiety, depression, dementia, memory and attention deficits,Alzheimer's disease, dysmenorrhea, narcolepsy, Reynaud's disease,intermittent claudication, Sjorgren's syndrome, migraine, arrhythmia,hypertension, absence seizures, myotonic muscle dystrophia, xerostomi,diabetes type II, hyperinsulinemia, premature labor, baldness, cancer,and immune suppression.

A satisfactory result can, in certain instances, be obtained at a dosageas low as 0.005 mg/kg i.v. and 0.01 mg/kg p.o. The upper limit of thedosage range is about 10 mg/kg i.v. and 100 mg/kg p.o. Preferred rangesare from about 0.001 to about 1 mg/kg i.v. and from about 0.1 to about10 mg/kg p.o.

EXAMPLES

The invention is further illustrated with reference to the followingexamples which are not intended to be in any way limiting to the scopeof the invention as claimed.

Example 1

General Reaction Scheme for the Syntheses of Compounds 1a-1f (see Table1)

1,4-Bis(2-aminobenzimidazol-1-yl)butane, 2HCl (Compound 1c). Asuspension of 1.2c-2HCl (1.1 g, 3.2 mmol) in anhydrous DMF (10 ml) waswrapped in alu-foil to exclude light. A solution of cyanogen bromide(0.7 g, 6.6 mmol) in anhydrous DMF (5 ml) was added dropwise. Themixture was stirred in a nitrogen atmosphere at ambient temperature forthree days, whereafter it was poured into ice-water. The precipitate wasfiltered off, washed with water and dried to leave 1c (0.42 g). M.p.292-294° C.

1,6-Bis(2-aminobenzimidazol-1-yl)hexane, 2HCl (Compound 1b) was preparedanalogously from 1.2b. M.p. 145-147° C.

1,3-Bis(2-aminobenzimidazol-1-yl)propane (Compound 1d) was preparedanalogously from 1.2d. The product was isolated as the free base. M.p.220° C. (with decomposition).

Example 2

1,3-Bis[(2-aminobenzimidazol-1-yl)methyl]cyclohexane (Compound 1a) wasprepared from 1.2a as described in Example 1 with the followingmodifications: The solvent was anhydrous NMP. The reaction time was 24hours. At the end of the reaction the mixture was poured into water andrendered alkaline by addition of aqueous sodium carbonate. Theprecipitate was filtered off and purified by column chromatography onsilica gel using a mixture of dichloromethane, methanol and aqueousammonia (9:1:0.1 v/v/v) as the eluent. Yield: 0.28 g (cis/trans mixture)which gradually decomposed upon melting.

α,α′-Bis(2-aminobenzimidazol-1-yl)-para-xylene (Compound 1f) wasprepared analogously from 1.2f. M.p. 287-289° C.

α,α′-Bis(2-aminobenzimidazol-1-yl)-meta-xylene (Compound 1g) wasprepared analogously from 1.2g. M.p. 279-280° C.

3,3′-Bis(2-aminobenzimidazol-1-yl)biphenyl (Compound 1i) was preparedanalogously from 1.2i. M.p. 160-163° C.

1,3-Bis(2-aminobenzimidazol-1-yl)benzene (Compound 1h) was preparedanalogously from 1.2h using DMF as the solvent. M.p. 270-275° C.

1,2-Bis(2-aminobenzimidazol-1-yl)ethane (Compound 1e) was prepared from1.2e in analogy with Example 2 using DMF as the solvent and a total offour equivalent of cyanogen bromide. The reaction time was 6 days.Yield: 0.13 g. M.p. 257-258° C.

Example 3

N,N′-Bis(2-aminophenyl)-1,4-butanediamine, 2HCl (Compound 1.2c): To asuspension of 1.3c (1.2 g, 3.64 mmol) in a mixture of abs. EtOH anddichloromethane (50 ml, 9:1) was added Pd-catalyst (0.1 g, 5% Pd onactivated carbon). The mixture was hydrogenated at ambient pressureuntil the H₂-uptake had ceased and thereafter filtered through celite.The filtrate was concentrated to a small volume under reduced pressure.Etheral hydrogen chloride, was added, and the product was isolated byfiltration. Yield: 1.14 g.

1,3-Bis(N-(2-aminophenyl)methylamine)cyclohexane, 2HCl (Compound 1.2a)was prepared analogously from 1.3a.

N,N′-Bis(2-aminophenyl)-1,6-hexanediamine, 2HCl (Compound 1.2b) wasprepared analogously from 1.3b.

N,N′-Bis(2-aminophenyl)-1,3-propanediamine, 2HCl (Compound 1.2d) wasprepared analogously from 1.3d.

N,N′-Bis(2-aminophenyl)ethylendiamine, 2HCl (Compound 1.2e) was preparedanalogously from 1.3e.

N,N′-Bis(2-aminophenyl)-meta-xylylenediamine, 2HCl (Compound 1.2g) wasprepared analogously from 1.3g.

N,N′-Bis(2-aminophenyl)-1,3-phenylenediamine, 2HCl (Compound 1.2h) wasprepared analogously from 1.3h.

N,N′-Bis(2-aminophenyl)-3,3′-diaminobiphenyl, 2HCl (Compound 1.2i) wasprepared analogously from 1.3i.

Example 4

N,N′-Bis(2-aminophenyl)-para-xylylenediamine (Compound 1.2f): To asuspension of 1.3f (8.7 g, 23.0 mmol) in a mixture of abs. EtOH and THF(500 ml, 1:1) was added sodium sulphide nonahydrate (55.3 g, 0.23 mol)and ammonium chloride (12.3 g, 0.23 mol). The resulting mixture washeated to reflux for three days. The solvent was removed by evaporationand the residue was triturated with water. The crude product wasfiltered off and extracted with a refluxing mixture of diethyl ether andmethanol (200 ml, 1:1). The cooled extract was concentrated and purifiedby column-chromatography on silica gel using a mixture of ethyl acetateand petroleum ether (1:1 v/v) as the eluent. Yield: 1.87 g.

Example 5

N,N′-Bis(2-nitrophenyl)-1,4-butanediamine (Compound 1.3c): A mixture of1,4-butanediamine (0.51 ml, 5.0 mmol), 1-fluoro-2-nitrobenzene (1.1 ml,10.0 mmol) and triethylamine (1.39 ml, 10.0 mmol) in anhydrous DMF (5ml) was heated to 100° C. over-night. The cooled mixture was poured intoice-water. The product was filtered off, washed with water and dried toyield 1.22 g (24%).

1,3-Bis[N-(2-nitrophenyl)aminomethyl]cyclohexane (Compound 1.3a) wasprepared analogously from 1,3-bis(aminomethyl)cyclohexane.

N,N′-Bis(2-nitrophenyl)-1,6-hexanediamine (Compound 1.3b) was preparedanalogously from 1,6-hexanediamine.

N,N′-Bis(2-nitrophenyl)-1,3-propanediamine (Compound 1.3d) was preparedanalogously from 1,3-propanediamine.

N,N′-Bis(2-nitrophenyl)ethylenediamine (Compound 1.3e) was preparedanalogously from ethylenediamine.

N,N′-Bis(2-nitrophenyl)-para-xylylenediamine (Compound 1.3f) wasprepared analogously from para-xylylenediamine.

N,N′-Bis(2-nitrophenyl)-meta-xylylenediamine (Compound 1.3g) wasprepared analogously from meta-xylylenediamine.

N,N′-Bis(2-nitrophenyl)-1,3-phenylenediamine (Compound 1.3h) wasprepared analogously from 1,3-phenylenediamine.

N,N′-Bis(2-nitrophenyl)-3,3′-diaminobiphenyl (Compound 1.3i) wasprepared analogously from 3,3′-diaminobiphenyl.

Example 6

1-(4-Aminophenyl)guanidine, Hl (Compound 3f): To a solution of1,4-phenylenediamine (1.08 g, 10.0 mmol) in a mixture of abs. EtOH (20ml) and THF (10 ml) was added methyl thiuronium iodide (1.69 g, 7.75mmol). The mixture was heated to 60° C. for 3 days. After cooling thesolvent was removed by evaporation and the residue was extracted withwater. The extract was evaporated to dryness and the residue was washedwith ether to leave 3f (1.93 g). M.p. 195-197° C.

Example 7

α,α′-Bis(3-phenylguanidine-1-yl)-para-xylene, 2HCl (Compound 3g): To asolution of aniline (1.37 ml, 15.0 mmol) in DMF (25 ml) was addedconcentrated hydrochloric acid (0.23 ml). The mixture was stirred for 30min prior to addition of a suspension ofN,N′-dicyano-para-xylylenediamine (0.7 g, 3.76 mmol) in DMF (10 ml). Theresulting mixture was heated to 100° C. for four days. The solvent wasremoved by evaporation under reduced pressure and the residue wasextracted with EtOH. The concentrated extract wascolumn-chromatographied on silica gel using a mixture of ethylacetateand petroleum ether (1:1) as the eluent, Etheral hydrogen chloride wasadded to the product-containing eluate. The product was filtered off anddried. Yield: 0.18 g. M.p. 204-207° C.

N,N′-dicyano-para-xylylenediamine: To a suspension ofpara-xylylenediamine (1.88 g, 3.8 mmol) in THF (50 ml) was added asolution of cyanogenbromide (1.06 g, 10.0 mmol in THF (50 ml). Thereaction vessel was wrapped in alu-foil and the mixture was left withstirring at ambient temperature for three days. The mixture was filteredand the filtrate was evaporated to dryness to leave the desired product(0.71 g).

Example 8

6-Amino-3-guanidinoacridine, HCl (Compound 3h): To a solution of3,6-diaminoacridine (0.5 g, 1.0 mmol) in concentrated hydrochloric acid(10 ml) was added cyanamide (0.18 g, 4.3 mmol). The mixture was heatedto 100° C. for 6 days. The cooled mixture was poured into ice-water andrendered alkaline by addition of aqueous sodium hydroxide. Theprecipitate was filtered off and fractionated by column-chromatographyon silica gel using a mixture of acetonitril, acetic acid and water(4:1:1 v/v/v) as the eluent. The product-containing fractions wereconcentrated and the product precipitated upon addition of etheralhydrogen chloride. Yield: 30 mg. M.p. above 305° C.

Example 9

α,α′-Bis(1-benzimidazolyl)-meta-xylene (Compound 7e): A solution of 1.2g (1.39 g, 4.37 mmol) in formic acid (5 ml) was heated to 80° C. for 30min. Excess formic acid was removed by evaporation and the residue wasstirred with ice-cold aqueous sodium carbonate. The product was filteredoff, washed with water and dried. Yield: 1.20 g.

Example 10

1,1′-(α,α′-para-xylylene)-3,3′-(α,α′-meta-xylylene)-bis(benzimidazolium)Bromide (Compound 7f): A mixture of 7e (0.46 g, 1.38 mmol) andα,α′-dibromo-para-xylene (0.36 g, 1.38 mmol) in DMF (70 ml) was heatedto 100° C. overnight. The solvent was removed under reduced pressure andthe crystalline residue was washed with dichloromethane to leave 7f(0.76 g). M.p. 292-294° C.

Example 11

cis,trans-1,4-Bis[(2-chlorobenzimidazol-1-yl)methyl]cyclohexane(Compound 7a): A mixture of1,4-bis(p-toluenesulfonyloxymethyl)cyclohexane (1.10 g, 2.43 mmol),2-chlorobenzimidazole (0.74 g, 4.85 mmol) and potassium carbonate (0.67g, 4.85 mmol) in abs. EtOH (20 ml) was heated to 75° C. for two days.The cooled mixture was poured into water and the precipitate wasfiltered off, washed with water and dried to yield 7a (0.61 g). M.p.247-253° C.

Example 12

cis,trans-1,4-Bis[2-(1-pyrrolidinyl)benzimidazol-1-yl)methyl]cyclohexane(Compound 7b): A mixture of 7a (0.25 g, 0.61 mmol) and pyrrolidine (2ml, 24 mmol) was heated to 80° C. for 2 hours. After cooling the mixturewas poured into water and the precipitate was filtered off. This crudeproduct was recrystallized from a mixture of 2-propanol anddichloromethane (9:1 v/v) to yield 7b (0.12 g). M.p. 258-260° C.

cis,trans-1,4-Bis[(2-(4-morfolinyl)benzimidazol-1-yl)methyl]cyclohexane,2HCl (Compound 7c) was prepared analogously from 7a and morpholine.Isolated as the hydrochloride. M.p. 286-288° C.

cis,trans-1,4-Bis[(2-(1-methylpiperazine-4-yl)benzimidazol-1-yl)methyl]cyclohexane(Compound 7d) can be prepared analogously from 7a and1-methylpiperazine.

Example 13

α,α′-Bis(1-(2-pyrimidyl)piperazin-4-yl)-para-xylene (Compound 5a): Amixture of 1(2-pyrimidyl)piperazine, 2HCl (2.0 g, 8.43 mmol),α,α′-dibromo-para-xylene (1.11 g, 4.21 mmol) and triethylamine (2.34 ml)in DMF (25 ml) was heated to 100° C. overnight. The cooled mixture wasfiltered and the precipitate was dissolved in water and renderedalkaline by addition of aqueous sodium hydroxide. The product wasfiltered off, washed with water and dried. Yield: 1.91 g. M.p. 193-195°C.

Example 14

α,α′-Bis(1-(2-pyrimidyl)-4-methylpiperazinium-4-yl)-para-xylene Iodide(Compound 5b). To a suspension of 5a (0.75 g, 1.74 mmol) in a mixture ofdichloromethane (10 ml) and DMF (1 ml) was added iodimethane (0.22 ml,3.53 mmol) and the mixture was stirred at ambient temperature for threedays. The product was filtered off, washed with dichloromethane anddried. Yield: 0.63 g. M.p. above 310° C.

Example 15

1,4-Bis(1-benzylbenzimidazol-2-yl)piperazine (Compound 5c): A mixture of1-benzyl-2-chlorobenzimidazole (1.21 g, 5.0 mmol), piperazine (0.22 g,2.5 mmol) and potassium carbonate (0.69 g, 5.0 mmol) in DMF (10 ml) washeated to reflux for three days. The cooled mixture was poured intoice-water. The precipitate was filtered off and washed with refluxingethyl acetate to leave 5c. Yield: 0.46 g. M.p. 247-248° C.

Example 16

1-(4′-Chlorobenzyl)-2-dimethylamino)-5-trifluoromethylbenzimidazoline(Compound 6d): To a solution of2-(4′-chlorobenzylamino)-5-trifluoromethylaniline, HCl (1 g, 2.97 mmol)in DMF (10 ml) was added triethylamine (0.36 g, 3.56 mmol) andN,N-dimethylformamide dimethyl acetate (0.84 g, 7.12 mmol). The mixturewas stirred at 50° C. overnight. The cooled reaction mixture waspartitioned between water and diethyl ether. The organic phase was driedand concentrated, and the residue was triturated with a mixture ofdiethyl ether and petroleum ether (1:1 v/v) to leave 5c. M.p. 107-109°C.

Example 17

All reactions in this example involving air sensitive reagents orintermediates were performed under nitrogen and in anhydrous solvents.Magnesium sulphate was used as drying agent in the workup-procedures andsolvents were evaporated under reduced pressure.

2-Amino-1-[3-(1,3,5-trimethylpyrazol-4-yl)phenyl]benzimidazole (Compound2d).

A mixture of 2-(3-(2-amino-1-benzimidazolyl)phenyl)-1,3,2-dioxaborinane(2.0 g, 6.82 mmol), 4-bromo-1,3,5-trimethylpyrazole (1.29 g, 6.82 mmol),tetrakis(triphenylphosphine)-palladium(0) (0.24 g, 0.20 mmol), sodiumhydrogen carbonate (2.29 g, 27.3 mmol), water (27 ml) and1,2-dimethoxyethane (54 ml) was stirred at reflux overnight. Aqueoussodium hydroxide (50 ml) was added and the mixture was extracted twicewith ethyl acetate (50 ml). The crude extract was purified bychromatography using silica gel and a mixture of ethanol (4%) anddichloromethane as eluent. The product was isolated as the free base.Yield 0.60 g, 28%. M.p. 198-200° C.

Method A

2-Amino-1-(4-dimethylaminobenzyl)-5-trifluoromethylbenzimidazole(Compound 2b).

A mixture of 2-amino-N-(4-dimethylaminobenzy!)-4-trifluoromethylaniline(5.2 g, 16.8 mmol), cyanogen bromide (2.31 g, 21.8 mmol) in DMF (75 ml)was stirred for three days at room temperature. Water (100 ml) wasadded, and the mixture was filtered. The filtrate was made alkaline withsodium hydroxide (2 M, 100 ml). The mixture was extracted twice withethyl acetate (100 ml). The crude extract was purified by chromatographyusing silica gel and a mixture of ethanol (4%) and dichloromethane aseluent. The product was isolated as the free base. Yield 0.92 g, 16%.M.p. 184-186° C.

2-Amino-1-[4-(4-chlorophenyl)-2-thiazolyl]benzimidazole Hydrochloride(Compound 2a) was prepared from2-amino-N-[4-(4-chlorophenyl)-2-thiazolyl]-aniline according to methodA. M.p. 220-223° C.

2-Amino-1-(4-phenyl-2-thiazolyl)benzimidazole (Compound 2c) was preparedfrom 2-amino-N-(4-phenyl-2-thiazolyl)aniline according to method A. M.p.229-231° C.

2-Amino-1-(4-(N-(2-thiazolyl)amino)phenyl)benzimidazole (Compound 2e)was prepared from 2-amino-4-(N-(2-thiazolyl)amino)phenyl)anilineaccording to method A. M.p. 218-220° C.

2-Amino-1-(4-acetamidophenyl)benzimidazole was prepared from2-amino-N-(4-acetamidophenyl)aniline according to method A. M.p.246-248° C.

2-(3-(2-Amino-1-benzimidazolyl)phenyl)-1,3,2-dioxaborinane was preparedaccording to method A from2-amino-3′-(1,3,2-dioxaborinan-2-yl)diphenylamine. M.p. 150-155° C.

2-Amino-1-(4-aminophenyl)benzimidazole Hydrochloride.

2-Amino-1-(4-acetamidophenyl)benzimidazole (1.78 g, 6.68 mmol) wasrefluxed in hydrochloric acid (25 ml) overnight. The crude mixture wasevaporated and triturated with diethyl ether. Yield 1.68 g, 96%, M.p.258-260° C.

1-(4-(2-Aminobenzimidazol-1-yl)phenyl)-3-phenylguanidine Hydrochloride(Compound 2f).

A mixture of 2-Amino-1-(4-aminophenyl)benzimidazole Hydrochloride (1.58g, 6.06 mmol), phenylcyanamide (2.79 g, 23.6 mmol) and acetonitrile (10ml) was refluxed for 3 days. The solid product was filtered off. Theproduct was recrystallized from acetonitrile (300 ml). Yield 1.3 g, 57%.M.p. 265-267° C.

Method B

2-Amino-N-(4-dimethylaminobenzyl)-4-trifluoromethylaniline.

A mixture of N-(4-dimethylaminobenzyl)-2-nitro-4-trifluoromethylaniline(6.0 g, 17.7 mmol), palladium on carbon (0.70 g, 5%), ethanol (200 ml)and tetrahydrofurane (175 ml) was stirred under hydrogen until 1.19 lwas consumed. The reaction mixture was filtered through a celite pad andevaporated. Yield 5.35 g, 98%. M.p. 160-162° C.

2-Amino-N-[4-(4-chlorophenyl)-2-thiazolyl]aniline was prepared fromN-[4-(4-chlorophenyl)-2-thiazolyl]-2-nitroaniline.

2-Amino-N-(4-phenyl-2-thiazolyl)aniline hydrochloride was prepared from2-nitro-N-(4-phenyl-2-thiazolyl)aniline according to method B. M.p.189-190° C.

2-Amino-N-(4-acetamidophenyl)aniline was prepared fromN-(4-acetamidophenyl)-2-nitroaniline according to method B. Isolated asan oil.

2-Amino-3′-(1,3,2-dioxaborinan-2-yl)diphenylamine was prepared from3′-(1,3,2-dioxaborinan-2-yl)-2-nitrodiphenylamine according to method C.M.p. 220-222° C. (for the hydrochloride).

Method C

2-Amino-N-(4-(2-thiazolyiamino)phenyl)aniline.

A mixture of 2-nitro-N-(4-(2-thiazolylamino)phenyl)aniline (1.2 g, 3.8mmol), sodium sulfide nona hydrate (4.61, 19.2 mmol), ammonium chloride(1.03 g, 19.2 mmol) and ethanol (40 ml) was stirred at reflux for 40 h.Water (50 ml) was added, the mixture was stirred and filtered. Yield0.49 g, 46%. M.p. 184-186° C.

N-(4-Dimethylaminobenzyl)-2-nitro-4-trifluoromethylaniline.

A mixture of 4-chloro-3-nitrobenzotrifluoride (5.05 g, 22.4 mmol),4-(dimethylamino)-benzylamine dihydrochloride (5.0 g, 22.4 mmol),potassium carbonate (9.29 g, 76.2 mmol) and dimethylformamide (60 ml)was stirred at room temperature for 3 days. Water (60 ml) was added andthe mixture was stirred for 0.5 h followed by filtration. Thecrystalline product was triturated with petroleum ether. Yield 6.08 g,80%. M.p. 158-160° C.

Method D

2-Nitro-N-(4-phenylthiazol-2-yl)aniline.

A mixture of 2-amino-4-phenylthiazole (12.5 g, 80.9 mmol),1-fluoro-2-nitrobenzene (12.5 g, 89.0 mmol), potassium carbonate (13.4g, 97.1 mmol) was stirred at 150° C. for 24 h. Water (100 ml) was addedand the mixture was extracted twice with 1,2-dichloroethane (50 ml). Thecrude extract was purified by chromatography on silica gel using tolueneas eluent. The product was isolated as the free base. Yield 7.95 g, 33%.M.p. 114-116° C.

N-[4-(4-Chlorophenyl)-2-thiazolyl]-2-nitroaniline was prepared accordingto method D.

2-Nitro-N-(4-aminophenyl)aniline was prepared according to method D.M.p. 110-112° C.

2-Nitro-N-(4-acetamidophenyl)aniline was prepared according to method D.M.p. 164-166° C.

3-(2-Nitrophenylamino)phenylboronic Acid was prepared according tomethod D using dimethylformamide as solvent and 90° C. as reactiontemperature. M.p. 195-196° C.

2-Nitro-N-(4-(2-thiazolylamino)phenyl)aniline.

2-Nitro-N-(4-aminophenyl)aniline (5.0 g, 21.8 mmol), 2-bromothiazole(3.58 g, 21.8 mmol) and potassium carbonate (3.01 g, 21.8 mmol) wasstirred at 150° C. for 24 h. Water (250 ml) was added and the mixturewas extracted with ethyl acetate (250 ml). The crude extract waspurified by chromatography using silica gel and a mixture of ethanol(4%) and dichloromethane as eluent. The product was isolated as the freebase. Yield 1.47 g, 22%. M.p. 195-197° C.

3′-(1,3,2-Dioxaborinan-2-yl)-2-nitrodiphenylamine.

A mixture of 2-nitrodiphenylamine-3′-boronic acid (27.0 g, 105 mmol),1,3 propanediol (9.55 g, 126 mmol), and toluene (500 ml) was refluxedfor 2 h with a Dean-Stark water separator attached. The solvent wasevaporated and the product was obtained as a yellow oil. Yield 31 g,99%.

Method E

1-(2-Methoxy-5-(trifluoromethyl)phenyl)-3-(3-(trifluoromethyl)phenyl)guanidineCompound 3a).

A mixture of 3-cyanamidobenzotrifluoride (0.40 g, 2.15 mmol),2-methoxy-5-triflouromethylaniline hydrochloric acid salt (0.53 g, 2.33mmol) and acetonitrile (20 ml) was stirred at reflux for 40 h. Thesolvent was evaporated. Dichloromethane (50 ml) was added and themixture was washed with saturated aqueous sodium hydrogen carbonate (50ml). The organic phase was purified by chromatography using silica geland a mixture of methanol (10%) and dichloromethane as eluent. Theproduct was isolated as the free base. Yield 0.40 g, 49%. M.p. 45-47° C.

1-(5-Chloro-2-methoxyphenyl)-3-(3-(trifluoromethyl)phenyl)guanidine(Compound 3c) was prepared according to method E. M.p. 94-96° C.

1,3-Bis(3-(trifluoromethyl)phenyl)guanidine (Compound 3d) was preparedaccording to method E. M.p. 108-110° C.

3-Cyanamidobenzotrifluoride.

A mixture of 3-aminobenzotrifluoride (15.0 g, 93.1 mmol), cyanogenbromide (12.2 g, 129 mmol) and diethyl ether was stirred at reflux for40 h. The crude mixture was purified by chromatography using silica geland a mixture of petroleum ether and dichloromethane as eluent (1:1).The product was isolated as the free base. Yield 5.2 g, 25%.

Method F

1-(4-Chlorobenzyl)-3-(3-triflouromethylphenyl)guanidine (Compound 3b).

A mixture of 3-cyanamidobenzotrifluoride (1.20 g, 6.45 mmol) and4-chlorobenzylamine hydrochloride (1.26 g, 7.09 mmol) was stirred at150° C. for 40 h. Dichloromethane (100 ml) was added and the mixture waswashed with saturated aqueous sodium hydrogen carbonate (100 ml). Theorganic phase was purified by chromatography using silica gel and amixture of methanol (10%) and dichloromethane as eluent. The product wasisolated as the free base. Yield 1.05 g, 50%. M.p. 103-105° C.

1-(2-Bromo-5-(trifluoromethyl)phenyl)-3-(5-(trifluoromethyl)phenyl)guanidine(Compound 3e) was prepared according to method F at 130° C. for 15 h.Isolated as an oil.

5-Chloro-1,3-bis(4-chlorobenzyl)-2-iminobenzimidazoline (Compound 4a).

A mixture of 2-amino-5-chloro-benzimidazole (9.4 g, 56.1 mmol),4-chlorobenzylchloride (9.93 g, 61.7 mmol), potassium carbonate (15.5 g,112 mmol) and dimethyl formamide (150 ml) was stirred at 50° C. for 20h. Water (150 ml) was added and the product was filtered off. The crudeproduct was purified by chromatography using silica gel and a mixture ofethanol (5%) and dichloromethane as eluent. The product was isolated asthe free base. Yield 0.37 g, 2%. M.p. 175-177° C.

2-Amino-5-chlorobenzimidazole.

To a mixture of 2-amino-4-chloroaniline (15.2 g, 106.6 mmol) anddimethylformamide (150 ml) was added cyanogen bromide (14.7 g, 138.6mmol). The mixture was stirred for 3 days. Water (300 ml) was added, andsome impurities were removed by filtration. Sodium hydroxide (212 ml, 2M) was added to the filtrate and the mixture was extracted five timeswith ethyl acetate (50 ml). The organic phase was washed with sodiumhydroxide (100 ml, 4M), dried and evaporated to dryness. The residue wasfinally triturated with petroleum ether to leave the product. Yield 9.4g, 53%.

2-Amino-4-chloroaniline was prepared from 4-chloro-2-nitroanilineaccording to method B.

Method G

2-Chloro-5-(6-imino-5,6,7,12-tetrahydrodibenzo[d,g][1,3,6]triazocin-12-yl)benzonitrile(Compound 4b).

A mixture of N,N-bis(2-aminophenyl)-3-chloro-4-cyanoaniline (2.6 g, 7.76mmol), cyanogen bromide (2.46 g, 23.3 mmol) and dimethylformamide (30ml) was stirred at room temperature for 5 days. Water (100 ml) wasadded, and the aqueous phase was washed with diethyl ether (100 ml). Tothe aqueous phase was added sodium hydroxide (1 M, 100 ml), and themixture was extracted twice with ethyl acetate (100 ml). The crudeextract was purified by chromatography using silica gel and a mixture ofethanol (10%) and dichloromethane as eluent. The product was isolated asthe free base. Yield 0.50 g, 28%. M.p. 225-228° C.

5,6,7,12-Tetrahydrodibenzo[d,g][1,3,6]triazocin-6-imine (Compound 4d)was prepared by method G. M.p. decomp.

N,N-Bis(2-aminophenyl)-3-chloro-4-cyanoaniline Hydrochloride

N,N-Bis(2-nitrophenyl)-3-chloro-4-cyanoaniline, palladium on carbon(0.70 g, 5%), ethanol (100 ml) was stirred under hydrogen until 2.5 lwas consumed. The reaction mixture was filtered through a celite pad,hydrogen chloride in methanol (4M, 30 ml) was added and the solvent wasremoved by evaporation. The residue was triturated with ethyl acetate toleave the crystalline product. Yield 3.8 g, 53%. M.p. 184-187° C.

N,N-Bis(2-nitrophenyl)-3-chloro-4-cyanoaniline.

A mixture of 3-chloro-4-cyano-aniline (40.0 g, 262 mmol),1-fluoro-2-nitrobenzene (40.7 g, 288 mmol) and potassium carbonate (36.2g, 262 mmol) was stirred at 180° C. overnight with a water collectorfitted to the condenser. Water (300 ml) was added followed by extractionwith diethyl ether. The product was isolated by chromatography usingdichloromethene as eluent. Yield 7.3 g, 7%. M.p. 165-167° C.

1-(2-Aminophenyl)-2-imino-3-phenyl-imidazolidine Hydrochloride (Compound4c) was prepared from 2-imino-1-(2-nitrophenyl)-3-phenyl-imidazolidineaccording to method B. M.p. 228-230° C.

2-Imino-1-(2-nitrophenyl)-3-phenyl-imidazolidine was prepared fromN-phenyl-N′-(2-nitrophenyl)ethylenediamine according to method A. M.p.257-259° C.

N-phenyl-N′-(2-nitrophenyl)ethylenediamine.

A mixture of 1-fluoro-2-nitrobenzene(15.5 g, 110 mmol) and potassiumcarbonate (15.2 g, 110 mmol) was stirred and a mixture ofN-methylpyrrolidone (20 ml) and N-phenylethylenediamine (15.0 g, 110mmol) was added over 1 h at room temperature. The mixture was stirredfor 1 h. Water (200 ml) was added crystals were filtered off andtriturated with petroleum ether. Yield 14.7 g, 52%. M.p. 64-66° C.

Example 18

cis-1,5-bis(2-amino-1-benzimidazolyl)cyclooctane (Compound 1j).

To a hot (60° C.) solution of 2-aminobenzimidazole (0.22 g; 1.65 mmol)in DMF (25 ml) was added sodium hydride (70 mg; 60% dispersion inmineral oil), and the mixture was stirred for 30 minutes prior toaddition of cis-1,5-bis(p-toluenesulfonyloxy)cyclooctane. The resultingmixture was stirred at 100° C. for four days, cooled and filtered. Thefiltrate was diluted with water and the precipitate was filtered off,washed with water and dried to yield the desired product (9 mg).

Example 19

Biological Activity

This example demonstrates the biological activity of the compounds ofthe invention. Compounds 1A and 1F of example 3, Compounds 1B of example2, Compound 1J of example 19, and Compound 7F of example 11 wereexamined.

In this experiment, small-conductance Ca²⁺-activated K⁺ channels (SKchannels, isoform 2) cloned from a rat cDNA library were stablyexpressed in HEK293 cells using standard procedures. The ionic currentthrough the channels was recorded in the whole-cell mode of thepatch-clamp technique.

Cells plated on coverslips are placed in a 15 μl perfusion chamber(flowrate˜1 ml/min), mounted on a IMT-2 microscope equipped withNomarski or Hoffmann optics. The microscopes are placed onvibration-free tables in grounded Faraday cages.

All experiments are performed at room temperature (20-22° C.). EPC-9patch-clamp amplifiers (HEKA-electronics, Lambrect, Germany) areconnected to Macintosh computers via ITC16 interfaces. Data are storeddirectly on the harddisk and analyzed by the IGOR software according tothe manufacturer's instructions.

The whole-cell configuration of the patch clamp technique is applied.Shortly described, the tip of a borosilicate pipette (resistance 2-4 MΩ)is gently (remote control system) placed on the cell membrane. Lightsuction results in a giga seal (pipette resistance increases to morethan 1 GΩ), and the cell membrane is then ruptured by more powerfulsuction. Cell capacitance is electronically compensated and theresistance between the pipette and the cell interior (the seriesresistance, Rs) is measured and compensated for. Usually the cellcapacitance ranges from 5 to 20 pF (depending on cell size), and theseries resistance is in the range 3 to 6 MΩ. Rs- as well as capacitancecompensation are updated during the experiments (before each stimulus).All experiments with drifting Rs-values are discharged.Leak-subtractions are not performed.

Solutions

The extracellular (bath) solution contains (concentration in mM): 144KCl, 2 CaCl₂, 1 MgCl₂, 10 HEPES (pH=7.4).

Test compounds are dissolved as 1000 times concentrated stock solutionsin DMSO, and then diluted in the extracellular solution.

In the experiments where the effect of channel activators is quantified(test 475), the intracellular (pipette) solution has the followingcomposition (concentration in mM):

144 KCl, 10 EGTA, 1.4 MgCl₂, 5.17 CaCl₂, and 10 HEPES (pH=7.2).

The calculated free concentration of Ca²⁺ in this solution is 100 nM,and hat of Mg²⁺ is 1 mM. In these experiments, the concentration ofCaCl₂ is 7.6 mM and hat of MgCl₂ is 1.2 mM to give calculated freeconcentrations of 300 nM and 1 mM, respectively.

Quantification

After establishment of the whole-cell configuration, voltage-ramps(usually −100 to +100 mV) are applied to the cell every 5 sec. A stablebaseline current is obtained within a period of 100-300 seconds andcompounds are then added by changing to an extracellular solutioncontaining the compound to be tested. Very little endogene current (<200pA at 100 mV compared to 2-20 nA SK current) are activated under thesecircumstances in native HEK293 cells.

An IC₅₀ value is calculated from the kinetics of the block. Thetime-course of the decrease in current is fitted to the followingequation:

I=I ₀*(1−(C/C+(K _(off) /K _(on))))*(1−exp(−(C*K _(on) +K _(off))*t)))

where

K_(off)=off-rate in s⁻¹

K_(on)=on-rate in M⁻¹s⁻¹

I₀=basal current in nA

C=drug concentration in μM

IC₅₀ equals the ratio K_(off)/K_(on).

The compounds of the invention tested in this experiment all showed abiological activity determined as IC50 in the sub-micromolar and lowmicromolar range, i.e. of from below 1 to above 10 μM.

What is claimed is:
 1. A compound represented by formula VII,

or a pharmaceutically-acceptable addition salt thereof, wherein Xrepresents NH₂, and A represents a radical of the formula—(CH₂)_(a)-D-(CH₂)_(b)—, wherein a and b, which may be identical ordifferent, represent the number 0, 1, 2, 3, 4 or 5, and D represents acycloalkyl group.
 2. The compound of claim 1, wherein A represents (cisand/or trans)-1,5-cyclooctylene; or (cis and/ortrans)-1,3-dimethylcyclohexane-α,α′-diyl.
 3. The compound of claim 2,wherein said compound is1,3-Bis((2-aminobenzimidazol-1-yl)methyl)cyclohexane; orcis-1,5-bis(2-amino-1-benzimidazolyl)cyclooctane; or apharmaceutically-acceptable addition salt there of.
 4. A pharmaceuticalcomposition comprising an effective amount of a compound according toclaim 1, or a pharmaceutically-acceptable addition salt thereof,together with at least one pharmaceutically-acceptable carrier ordiluent.
 5. The pharmaceutical composition according to claim 4, whereinthe compound is 1,3-Bis((2-aminobenzimidazol-1-yl)methyl)cyclohexane; orcis-1,5-bis(2-amino-1-benzimidazolyl)cyclooctane.